1. Field of the Invention:
This invention relates to a method and apparatus for attaching a strip of reinforcing tape, consisting essentially of a synthetic resin, onto a slide fastener chain, particularly at the portion of the fastener where a pin member and pin-receiving box member are provided on the opposed stringer tapes.
A fastener chain consists of a pair of continuous length stringers each having alternate fastening element-containing and element-free sections. The so-called intermittent fastener chain of this type, after being cut off at the section devoid of the fastening elements to form an individual fastener, has a pin member attached to one stringer and a pin-receiving box member attached to the other opposing stringer, these being provided at the sections devoid of the fastening elements, known as "space" portions in the art. The opposed stringer tapes are joined by inserting the pin member into the box member. When the pin and box members are attached to the fastener chain directly, the fastener chain does not possess sufficient durability owing to damage incurred by frictional contact with these elements during use. Accordingly, it is conventional practice to attached reinforcing strips of synthetic resin to the fastener chain at the portions where the pin and box members are to be affixed, prior to affixing these members. The present invention relates to a method and apparatus for automatically attaching these reinforcing strips to the intermittent fastener chain at the space portions thereof in successive fashion before the fastener chain is cut off to form individual fasteners.
2. Description of the Prior Art:
A method and apparatus for the foregoing purpose have already been disclosed in Japanese Patent Publication No. 17017/1972 or U.S. Pat. No. 3,671,347 and, to the Applicant's knowledge, represent the highest level in the art. Nevertheless, the invention disclosed in the above publication does possess several disadvantages. Specifically, in folding a strip of reinforcing tape around one edge of the fastener, the particular arrangement of the apparatus is such that the strip of reinforcing tape protrudes a certain distance beyond the opposite edge of the fastener once it has been attached thereto. This protruding length of tape represents wasted material since it does not contribute to reinforcement of the fastener. Furthermore, despite the fact that one edge of the fastener usually includes an embedded woven yarn which makes that edge thicker than the remaining portion of the fastener, which is flat, the entire reinforcing tape is pressed adhesively onto thickened and flat portions of the fastener at the same time. This not only causes wrinkling and the formation of air bubbles between the reinforcing tape and fastener, which can in turn cause the reinforcing tape to peel off, but also affects the positional accuracy with which the reinforcing tape is attached.